The invention relates to a method for the wet treatment or processing of substrates in a container into which at least one fluid is introduced and drained via an overflow device. Furthermore, the invention relates to a device for the wet treatment of substrates in a container which is provided with at least one fluid inlet and one fluid overflow device with openings for draining a fluid.
Methods and devices of the above-mentioned kind are known, for example from U.S. Pat. No. 4,722,752, from EP A 0 385 536, and are also described in the unpublished documents DE-A-44 130 077 and DE-A-195 46 990 of the same applicant. The upper side of the container holding the fluid and the substrates is provided with overflow devices, whereby the fluid is introduced from below and upwardly, passing the substrates, and drains off through the overflow openings or edges at the upper side of the container. After the wet treatment, for example after a rinsing process, the substrates are lifted--by a more or less complicated mechanism--either together with a substrate carrier or directly out of the fluid or the container, with the overflow drain providing for particles and other contaminants at the fluid surface to be carried off into the overflow device by the flow and essentially not to stick to the substrates while lifting the substrates out of the fluid.
The mechanical devices for securely and uniformly lifting the substrates out of the fluid or out of the container are very costly and complicated. Moreover, the lifting mechanisms require a relatively large space within the container because they have to grip underneath the substrate carrier or under the substrates and lift them up. Apart from the fact that the container dimensions have to be relatively large, a relatively large fluid consumption is involved with this if the fluid has to be changed or replaced.
A particular disadvantage on lifting the wafers out of the container is also that very accurately manufactured guides for the wafers on the lifting mechanisms and within the hood for the wafers that is arranged above the container have to be formed in order to hold the wafers securely and reliably within a defined position during the lifting-off out of the container. The manufacturing costs for such guides are high because of the very precise manufacturing that is required and, additionally, with the commonly known devices damage or breaking of the substrates on lifting them out of the container can be avoided only by an additional adjusting mechanism.
AT 208 307 discloses a dosing apparatus for proportionally introducing chemical solutions into periodically charged containers. The dosing apparatus includes a chemical container that is hermetically sealed from the outside and that is disposed over a liquid or fluid container. Provided in the fluid container is an air-displacement bell that is opened downwardly toward the fluid container and at the highest location communicates via a connecting pipe with the hermetically sealed chemical container 1. Disposed in the interior of the sealed chemical container is a float with a tube, the free opening of which intersects the lower edge of the float. If the fluid container is entirely or partially filled, a corresponding quantity of air is displaced into the hermetically sealed chemical container, so that there exists in this sealed container an excess pressure that presses the chemical solution through the opening at the lower connecting end of the float, so that a corresponding quantity of chemical solution flows through a hose for the dosed introduction of the chemicals into the fluid container. Such a dosing apparatus enables the dosing of a fluid proportional to a fluid quantity that is to be filled in a liquid container by means of air displacement, so that this known apparatus serves a basically different purpose, entirely aside from the fact that the container for this purpose must be hermetically sealed in order to be able to generate an overpressure.
It is an object of the invention to provide or create a method and a device of the kind mentioned in the introduction which is substantially simpler not only with regard to the method but also to the structural requirements and, nevertheless, guarantees a secure and reliable handling of the substrates.